Creating a Disk Store or Using the Default
You can create a disk store for persistence and/or overflow or use the default disk store. Data from multiple tables can be stored in the same disk store.
Default Disk Stores
Tables that do not name a disk store but specify persistence or overflow in their CREATE TABLE statement are automatically assigned to the default disk store, GFXD-DEFAULT-DISKSTORE. Also, gateway, AsyncEventListener, and DBSynchronizer queues always use the default disk store. The default diskstore is saved to the GemFire XD data store's working directory, unless you change the value of the sys-disk-dir boot property to specify another location.
Never move or modify the datadictionary subdirectory or any other disk store directory. If the data dictionary or a disk store directory of a GemFire XD locator or data store member is unavailable, other members may fail to start if the "offline" member potentially holds a more recent copy of the data. In this case, members will display a ConflictingPersistentDataException when attempting to start.
Creating a Named Disk Store
You create a named disk store in the data dictionary using the CREATE DISKSTORE DDL statement. You then assign the disk store to an individual table by specifying the disk store in the table's CREATE TABLE DDL statement. You can store data from multiple tables and queues in the same named disk store.